The present oil mist generators operating on a vortex principle enjoy a best combination of properties as compared to other known types of the oil mist generators, namely, as compared to the generators provided with a throat of a venturi. This results from the fact that the vortex type generator enables the rotating flow of gas to be moved with a higher rate and permits an increase in the magnitude of the differential in pressure across the suction duct supplying the oil into the flow of gas.
Known in the prior art is an oil mist generator which operates on a vortex principle (cf. USSR Inventor's Certificate No. 448,891, Int. Cl. B 05 B 7/10). The generator includes an oil storage chamber, a cover having an oil mist outlet, a vortex chamber for creating a rotating flow of gas and having tangentially disposed inlets for a pressurized gas and a long cylindrical outlet axially arranged and connecting the vortex chamber with an intermediate chamber which, in turn, is in communication with the oil storage chamber. As the pressurized gas is directed through the tangentially arranged inlets into the vortex chamber, the flow of gas develops significant axial and tangential velocities, with the result that a suction area is created on the outer periphery of the vortex chamber outlet, which area is in communication with the intermediate chamber through passageways.
It should be noted that the long cylindrical outlet tends to slow down the flow of gas, thus reducing both flow rate and quality of oil atomization.
Furthermore, in the known oil mist generator, the oil is delivered into the intermediate chamber and directed therein towards the outlet of the vortex chamber through the corresponding passageways which fail to provide a significant interaction surface between the oil and the flow of gas as it moves therepast.
The disadvantages mentioned hereinabove are eliminated in a known vortex type generator (cf. U.S. Pat. No. 3,515,676, U.S. Cl. 252-359), which comprises a vortex chamber adapted for creating a rotating flow of gas and provided with tangentially disposed inlets and an axially disposed outlet, and an interaction chamber having tangentially arranged passageways supplying the oil into the rotating flow of gas moving out of the vortex chamber outlet. As the pressurized air is forced through the tangentially arranged inlets into the interior of the vortex chamber the flow of gas develops significant axial and tangential velocities. The rotating flow of gas, as it leaves the outlet of the vortex chamber, creates a suction area in the interaction chamber, which suction causes the liquid to be aspirated thereinto. The liquid is directed from the interaction chamber into the flow of gas in the direction of the tangential gas velocity, thus increasing the degree of liquid atomization which also increases with increase in ratio between the contact area of the gas flow and the volume of liquid to be atomized.
The generator is further provided with a lubricant flow regulator valve used for adjustably controlling the quantity of liquid to be atomized.
However, such a mist generator of the vortex design fails to provide a sufficient suction at the outlet of the vortex chamber for the atomization of high viscosity oil. This causes the oil to be preheated to a relatively high temperature, thus resulting in an excessive expenditure of energy.
Furthermore, a low suction in the interaction chamber of the known generator is inadequate to provide a wide adjustment range of the suction and, hence, of the amount of oil to be aspirated into the rotating flow of gas.
Also known in the art is an oil mist generator (cf. U.S. Pat. No. 3,605,942, U.S. Cl. 184-6.26) which in, addition to the members mentioned hereinabove, is further provided with a screen aligned with the vortex chamber and adjustable toward and away from the vortex outlet, and with an auxiliary oil channel arranged externally of the vortex chamber and aligned therewith, said channel being mounted for movement toward and away from the vortex outlet. In operation, said oil mist generator, when used in combination with the screen adjustable toward and away from the vortex outlet, permits the suction and the amount of oil aspirated into the rotating flow of gas, as well as the size and quantity of particles in the oil mist to be somewhat widely controlled. Said oil channel provides the useful suction area to be created in the axial zone of the rotating flow of gas moving outside the vortex chamber as well as on the outer periphery of the vortex chamber outlet. The supplying of oil through said oil channel makes possible to provide a high density mist. Moreover, such a generator enables the ratio between the contact area of gas flow and the volume of oil to be atomized to be increased with simultaneous increase in mist dispersity.
The auxiliary oil channel being arranged outside the vortex chamber, the axial velocity of the rotating flow of gas is oppositely directed with respect to the oil flowing in the auxiliary channel, thus resulting in deceleration of oil flow at the outlet of said channel.
Furthermore, the oil exiting from the outlet of the auxiliary channel fails to be directed in the zone of the rotating flow of gas of maximum tangential velocity, besides the time of gas and oil interaction is insufficient to effect thorough atomization.
In addition, such an oil mist generator for changing the oil mist density, the amount of liquid to be atomized and the particle size utilizes a relatively large number of elements incorporated therein, which complicates its adjustment and control.